From 7670a7d964dd01d4e1b61bbed400e16e4f2ec481 Mon Sep 17 00:00:00 2001
From: Vyr Cossont <VyrCossont@users.noreply.github.com>
Date: Sat, 23 Nov 2024 13:43:00 -0800
Subject: [PATCH] Special-case literal null expires_in for v2 filter PUT

---
 internal/api/client/filters/v2/filterput.go | 39 ++++++++++++++++++---
 internal/processing/filters/v2/update.go    | 13 ++++---
 2 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/internal/api/client/filters/v2/filterput.go b/internal/api/client/filters/v2/filterput.go
index cde03360d..2b440d5ca 100644
--- a/internal/api/client/filters/v2/filterput.go
+++ b/internal/api/client/filters/v2/filterput.go
@@ -18,7 +18,10 @@
 package v2
 
 import (
+	"bytes"
+	"encoding/json"
 	"errors"
+	"io"
 	"net/http"
 
 	"github.com/gin-gonic/gin"
@@ -180,12 +183,43 @@ func (m *Module) FilterPUTHandler(c *gin.Context) {
 		return
 	}
 
+	// If the request is JSON:
+	// Explicitly check whether `expires_in` is a null literal (vs. not being set at all).
+	hasNullExpiresIn := false
+	if c.ContentType() == gin.MIMEJSON {
+		// To do this, we need to read the request body twice, once here and once below for the form, so we buffer it.
+		// If a filter update request is bigger than a megabyte, somebody's messing with us.
+		bodyBytes, err := io.ReadAll(io.LimitReader(c.Request.Body, 1024*1024))
+		if err != nil {
+			apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
+			return
+		}
+		c.Request.Body = io.NopCloser(bytes.NewReader(bodyBytes))
+
+		// Partially parse the body as a JSON object.
+		requestJSONObject := map[string]json.RawMessage{}
+		if err := json.Unmarshal(bodyBytes, &requestJSONObject); err != nil {
+			apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
+			return
+		}
+
+		// Try to parse the `expires_in` field as a literal null.
+		if raw, found := requestJSONObject["expires_in"]; found {
+			hasNullExpiresIn = string(raw) == "null"
+		}
+	}
+
 	form := &apimodel.FilterUpdateRequestV2{}
 	if err := c.ShouldBind(form); err != nil {
 		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
 		return
 	}
 
+	// Interpret a literal null `expires_in` as unsetting the expiration date.
+	if hasNullExpiresIn {
+		form.ExpiresIn = util.Ptr(0)
+	}
+
 	if err := validateNormalizeUpdateFilter(form); err != nil {
 		apiutil.ErrorHandler(c, gtserror.NewErrorUnprocessableEntity(err, err.Error()), m.processor.InstanceGetV1)
 		return
@@ -283,11 +317,6 @@ func validateNormalizeUpdateFilter(form *apimodel.FilterUpdateRequestV2) error {
 		}
 	}
 
-	// Interpret zero as indefinite duration.
-	if form.ExpiresIn != nil && *form.ExpiresIn == 0 {
-		form.ExpiresIn = nil
-	}
-
 	// Normalize and validate updates.
 	for i, formKeyword := range form.Keywords {
 		if formKeyword.Keyword != nil {
diff --git a/internal/processing/filters/v2/update.go b/internal/processing/filters/v2/update.go
index 0d443d58e..d5b5cce01 100644
--- a/internal/processing/filters/v2/update.go
+++ b/internal/processing/filters/v2/update.go
@@ -21,8 +21,6 @@
 	"context"
 	"errors"
 	"fmt"
-	"time"
-
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
@@ -30,6 +28,7 @@
 	"github.com/superseriousbusiness/gotosocial/internal/id"
 	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
+	"time"
 )
 
 // Update an existing filter for the given account, using the provided parameters.
@@ -68,10 +67,16 @@ func (p *Processor) Update(
 		filterColumns = append(filterColumns, "action")
 		filter.Action = typeutils.APIFilterActionToFilterAction(*form.FilterAction)
 	}
-	// TODO: (Vyr) is it possible to unset a filter expiration with this API?
 	if form.ExpiresIn != nil {
+		expiresIn := *form.ExpiresIn
 		filterColumns = append(filterColumns, "expires_at")
-		filter.ExpiresAt = time.Now().Add(time.Second * time.Duration(*form.ExpiresIn))
+		if expiresIn == 0 {
+			// Unset the expiration date.
+			filter.ExpiresAt = time.Time{}
+		} else {
+			// Update the expiration date.
+			filter.ExpiresAt = time.Now().Add(time.Second * time.Duration(expiresIn))
+		}
 	}
 	if form.Context != nil {
 		filterColumns = append(filterColumns,